Accord.Controls.SliderControl.TurnControl_MouseDown C# (CSharp) Метод

        private void TurnControl_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                if (isHorizontal)
                {
                    if (
                        (e.X >= leftMargin) &&
                        (e.X < ClientRectangle.Width - leftMargin) &&
                        (e.Y >= topMargin) &&
                        (e.Y < ClientRectangle.Height - topMargin))
                    {
                        int cx = e.X - ClientRectangle.Width / 2;
                        manipulatatorPosition = (float)cx / (ClientRectangle.Width / 2 - leftMargin);
                        tracking = true;
                    }
                }
                else
                {
                    if (
                        (e.X >= leftMargin) &&
                        (e.X < ClientRectangle.Width - leftMargin) &&
                        (e.Y >= topMargin) &&
                        (e.Y < ClientRectangle.Height - topMargin))
                    {
                        int cy = ClientRectangle.Height / 2 - e.Y;
                        manipulatatorPosition = (float)cy / (ClientRectangle.Height / 2 - topMargin);
                        tracking = true;
                    }
                }

                if (tracking)
                {
                    this.Capture = true;
                    this.Cursor = Cursors.Hand;

                    NotifyClients();
                    // start time, which is used to notify
                    // about manipulator's position change
                    ticksBeforeNotificiation = -1;
                    timer.Start();
                }
            }
        }